There is a growing interest within the design, manufacturing, and graphics communities in building systems and methods for digitizing the shape and appearance of three-dimensional objects. In general, these systems and methods involve obtaining information about an object and then transforming the shape, contour, color, and other information into a digitized model of the object. A digitized model of the shape and appearance of a physical object may have many applications, including: product design; reverse engineering; museum archiving; creation of models for visual simulation, movie making, videogames, and home shopping; architectural preservation; engineering retrofits; virtual reality flythroughs; and archiving importance objects, such as sculptures, historic buildings, and archeological sites. A physical replica of an object may be produced from a digitized model using a rapid prototyping technology, such as stereolithography. Other fields that may benefit from three-dimensional object shape and appearance information include reconstructive and plastic surgery, dentistry, biology, and internal medicine.
In one class of three-dimensional object scanning systems, a triangulation system projects beams of light on an object and determines three-dimensional spatial locations of points where the light reflects from the object. Based on the reflected light, the triangulation system determines the coordinates of the points of reflection by triangulation. A single dot scanning system sweeps a single beam of light over the object, whereas a scan line system sweeps a plane of light across the object. A single dot scanning system with a linear reflected light position detector can digitize only a single point at a time. Single dot scanning systems typically are used for applications, such as industrial engineering, in which scanning speed is not critical. Scan line systems typically detect reflected scan lines with a two-dimensional imager, such as a charged coupled device (CCD) camera, which may be mounted on a rotating arm or a moving platform. Typically in such systems, either the object moves relative to the camera and line scanner or the camera and line scanner move around the object.
In one approach, a shape digitizing system includes two laser stripe scanners that are operable to simultaneously scan two light beams in two dimensions across a three-dimensional object. Each laser stripe scanner includes a laser stripe generator that is configured to project a flat plane of light and a galvanometric scanner that includes a motor and a rotatable mirror.
Other systems for scanning light beams have been proposed. For example, in one approach, a scanning system includes two laser sources that are configured to produce respective laser beams that are directed toward a rotating polygonal mirror along different beam paths. In this system, the polygonal mirror scans the laser beams in the same direction and in the same scan plane, but delayed in time with respect to each other. In another approach, a two-dimensional serial and field multiplexing holographic scanner includes multiple rows of holograms on a disk to achieve serial multiplexing and a reflector to focus a scanning beam on different field points to achieve field multiplexing.